Published at 3:42 PM PDT on Jul 29, 2009 | Updated at 1:37 PM PDT on May 5, 2009

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It’s been percolating for a while, but the coffee war between McDonalds and Starbucks is about to boil over.

McDonalds has been rolling out its specialty coffee line since 2006 but the effort has resembled more of a slow drip. On Tuesday the fast food giant launches its first set of national advertisements taking aim at the ubiquitous coffee chain.

The fast food giant is hoping its McCafé line will displace the Starbucks brand as the go-to caffeine delivery system for Americans, and they’re using television, radio and Internet advertising to drive the message home.

Their first slate of ads play on the McCafé accent mark. Words such as "chore" and "rinse" are given accent marks on the "e" so they rhyme with McCafé. That spot ends with the phrase, "McCafé your day."

Another shows a woman standing at a bus stop looking annoyed, while a smiling man holding a McCafé mocha has turned his commute into a commuté. The ad goes on to say that McCafé makes a better day "possiblé."

McDonalds denies that it is taking direct aim at Starbucks with the ads, but last year they ran a billboard in Seattle, Starbucks’ home turf, that said, “Four bucks is dumb.” The billboard was later pulled at the request of the company’s president Don Thompson, but it’s obvious that McDonalds will go after Starbucks on a price point basis.

McDonald's espresso-based coffee drinks typically range from $2.29 for a 12-ounce cup to $3.29 for 22 ounces. By contrast, a caffè mocha at a Starbucks in Chicago ranges from $3.10 for a 12-ounce cup to $3.95 for 20 ounces, according to The Wall Street Journal.

Starbucks is not going to suffer the ad blitz lightly. The coffee chain launched a campaign to counter the McDonalds push Sunday with a full-page ad in The New York Times.

Unsnobby Coffee From McDonalds

Their push will emphasize quality over, well, cheap coffee. One of their ads says: “Beware of a cheaper cup of coffee. It comes with a price," and another says, "If your coffee isn't perfect, we'll make it over. If it's still not perfect make sure you're in a Starbucks."

Starbucks also plans to lean on its Internet savvy customers with advertisements on Facebook and Twitter.